Experimental Study on Mechanical Properties of Paste Backfill with Flue-Gas Desulphurisation Gypsum under Combined Action of Dry–Wet Cycles and Chloride Erosion

Flue-gas desulphurisation gypsum—a solid waste from power plants—can be used to prepare paste backfill for reducing costs. Most backfills are exposed dry–wet cycles and chloride salt-rich water in mines. Therefore, the mechanical properties damage mechanisms of with desulphurised gypsum under coupling action erosion due different concentrations were investigated using methods such as visual observation, mass measurement, uniaxial compression, acoustic emission, Fourier-transform infrared spectroscopy, X-ray diffraction analysis, field-emission scanning electron microscopy. With an increasing number cycles, mass, elastic modulus, strength exhibited trend first then decreasing. The failure mechanism changed mainly vertical fractures alternating development horizontal fractures. surface denudation effect specimens a solution higher concentration was more severe same cycles. In this study, laws governing change, degree denudation, pattern gypsum-filled salt numbers derived.